This proposal seeks support to acquire a fluorescence activated cell sorter at Cornell University where there is no longer a viable cell sorter. The instrument will support a user group currently consisting of 22 faculty who have 32 NIH research grants plus several NSF and USDA/NRI grants. They also have 3 NIH (T32) training grants. The instrument will thus fulfill needs for cytometry in these NIH sponsored research programs, enhancing productivity of ongoing research and augmenting the training programs, which can then include cytometry. The 22 faculty will use cytometry in a wide range of studies. These include cell cycle regulation, signaling by cytokines and hormones, cellular response to infection, calcium mobilization, apoptosis, leukocyte typing, mitochondrial function, cell differentiation, ectopic gene expression, and transcriptional regulation. The flow cytometry facility will be directed by Andrew Yen. He has had experience doing flow cytometry since he was a graduate student at the Sloan- Kettering Institute when the first commercial machines (BioPhysics, Mahopac, NY) were acquired in the laboratory of his mentors. He is still at the bench in flow cytometric applications. An experienced technician will do day-to-day running, and the director will do trouble shooting and experimental design, as well as data interpretation, with users. The organizational structure will consist of a director and a guidance committee made of 6 rotating members of the user community and the Director of Research and Graduate Education. User fees will be charged and accounting support for the facility will be by the Dept. of Biomedical Sciences. An educational program consisting of lectures and laboratories in two existing courses, "Cell Physiology and Genomics Laboratory" and "Methods Minicourse" and an annual research symposium will promote education of the Cornell community in applications of flow cytometry. The flow cytometry funding will also sponsor a regular users meeting. Secretarial support for these courses, the program and the user meetings, including announcements, technical bulletins, and course materials, will be provided by Biomedical Sciences. Continuing institutional commitment to flow cytometry will be provided as $150,000 over the first three years and a guaranteed service contract thereafter for the life of the instrument. The instrument requested is a Dako-Cytomation basic MoFlo plus a UV-vis, vis, and HeNe laser to provide independent UV, vis/488, and red excitation.